Developer Mode Extensions

Developer Mode on Google Chrome is an advanced mode allowing software developers to test their apps. Are you a software developer? Have you activated it willingly? If yes and yes, you do not need to worry about the “Disable developer mode extensions” pop-up alert you see in the top-right corner of your web browser. It is the opposite if you are sure you have not enabled this mode yourself because this might indicate that some kind of malicious Google Chrome extension has been added to the list of add-ons. In such a case, you must immediately open the Add-ons Manager and closely inspect all the extensions installed. Have you found unknown extensions or extensions which should not be there? Delete them all without consideration because malicious software might be using them. In most cases, extensions in Developer Mode indicate the presence of advertising-supported applications (adware), browser hijackers, and potentially unwanted programs on the system, but it should be noted that this list of untrustworthy programs using Developer Mode extensions is not complete.

Malicious applications are being developed every day, so Google Chrome developers have updated it to display an alert informing about active extensions in Developer Mode in order to help computer users to stay safe. The alert below is displayed at the upper-right part of the browser when those who encounter Developer Mode Extensions open Google Chrome:

Disable developer mode extensions

Extensions running developer mode can harm your computer. If you’re not a developer, you should disable these extensions running in developer mode to stay safe.

This alert should only be shown to users when a non-Chrome Store extension (such an extension which cannot be found and installed from the Chrome Web store) in Developer Mode is installed, so you must go check the list of extensions immediately if a pop-up message has been displayed to you. Of course, you are not expected to do anything if you have activated this mode yourself. Unfortunately, it often turns out after checking all active extensions that untrustworthy software has installed its extension. Untrustworthy applications might use those extensions to perform a number of activities users find undesirable. For example, ad-supported programs might display pop-ups, inject advertisements into pages, and track users’ online activities. In the case of browser hijackers, they often install extensions to alter browsers’ settings (e.g. a default homepage and search provider) easily. It is only possible to put an end to these undesirable activities by deleting a malicious extension working in Developer Mode and the remaining components of malware. Keep in mind that untrustworthy extensions do not always activate Developer Mode, so you still cannot blindly trust extensions you do not know or find installed without your knowledge.

Since we already know why Google Chrome can start showing the “Disable developer mode extensions” alert and what to expect from those malicious Developer Mode Extensions, we should now discuss how they are usually installed on browsers. Researchers can distinguish three main methods malicious extensions use to show up on users’ web browsers. First, Developer Mode is enabled in the Add-ons Manager (a tick needs to be put in the box next to Developer Mode at the top) by malware, and then the extension is loaded from a local file/folder. Second, malicious software copies the extension directly into the Google Chrome browser’s folder and then modifies its configuration to load the extension. Third, malware, usually a browser hijacker, modifies the shortcut of Google Chrome so that its extension would be loaded each time a computer user double-clicks on the browser’s shortcut seeking to open it. It should be noted that decent extensions rarely activate Developer Mode, so if your web browser has displayed a pop-up alert, this might indicate the successful installation of a malicious application. The situation might, of course, be different in your case, so do not take our words for granted.

Do not panic even if you have discovered a malicious extension working in Developer Mode installed because it will not be that hard to delete it. You can either go to remove this malicious extension through the Add-ons Manager or reset your browser to default settings. Security specialists usually recommend employing the latter method because other important changes could have been applied too and now they need to be undone – the browser reset will take care of that. It should be repeated one more time that software developers who have activated this Developer Mode for testing apps and then noticed a pop-up alert after launching Google Chrome again do not need to do anything but close the alert (click Cancel to close it instead of Disable).